Inductance coil



Patented Nov. 17, 1925.

UNITED STATES PATENT OFFICE.

FREDERICK J. GIVEN, OF EAST ORANGE, TRIO COMPANY, INCORPORATED, F YORK.

NEW JERSEY, ASSIGNOR TO WESTERN ELEG- NEW YORK, N. Y., 'A CORPORATION OF NEW INDUCTANCE COIL.

Application filed June 30, 1923. Serial No. 648,702.

Orange, in the county of Essex, State of New Jersey, have invented certain newand useful Improvements in Inductance Coils, of which cise, and. exact description. I

This invention relates to inductance coils.

An object of this invention is to provide a unitary structure having a urality of inductance windings, the mutual inductance between which. is substantially zero.

One form of this invention hereinafter described in detail comprises a hollow ringshaped core forming a shell structure about an inner winding, at the same time forming a toroidal core for anouter winding. Since these two windings have their turns at right angles to each other, it follows that the mu tual inductance between them is substan tially zero. 7

Such a unitary structure is capable of many uses in telephone or other signaling systems, the coils beingcapable of use, for example, in loading-units or loading simultaneously phantom and side circuits or' as inductances "in filters or other places where the mutual inductance between the coils should be negligible.

Fig.1 represents a plan view of a toroidal shaped device having its windings arranged in accordance with this invention; Fig. 2 is a sectional view of the device of Fig. 1; Fig. 3 represents this invention embodied in an inductance device of the air core type; Fig. 4 represents an electric wave filter, the inductance coils of which may be constructed in accordance with this invention;

and Fig. 5 illustrates how a plurality of-the devices of this invention may be arranged;

to form a filter.

Referring to the form of this invention disclosed in Fi s. l and 2, a toroidal shaped member 6 is uscloscd in which a suitable winding 7 of a plurality of layers is embedded. The toroid 6 may be of'any suitable magnetic material such as iron dust core material and may comprise two annular rin s, the opposing faces of which are groove to provide the necessa space for the coil 7. The two sections 0 the toroid may be held together by suitable bolts such as at the oints 8, 9 and 10.

After t e winding 7 has been embedded in the following is a full, clear, con-- the surface of .elements of such a filter the iron dust core material and the two halves of the toroid have been clamped to gather, an additional winding 11 is wound in a plurality of turns or layers with a, uniorm distribution around the entire surface of the toroid.

Due to the fact that the planes of the 7 turns of windings 7 and 11-are mutually at right angles, istin'gbetween the two windings 7 and 11 is substantially zero, If the winding 7 is embedded in such a position in the core that the core at right angles to follows substantially the path of a line 0 E force around the winding, the type of coil of Fig. 2 has substantially no external magnetic field, so that the coils 7 and'll may be placed adjacent other devices of a similar type with a resulting economy botli of material and space. A plurality of inductance devices such. as that shown in the Windin .Fig. 2 may be employed, for example, in the electric wavefilter of the type shown in Fig.- 4. The filter shown therein is of the low-pass type of a plurality of sections com-. prising series inductances- 12 to 17, and shunt capacities 18- to 22. The inductance must be carefully designed in order to insure the proper frequency transmission characteristic, and especially when the filter is of the type shown in Fig. 4, there must be no mutual inductance between the separate inductance elements; The inductance device of Fig. 2 may therefore be safely employed in such a filter in which winding 7 may be used as inductance 12, winding 11 as inductance l3 and similar windings from similar structures .may be employed for the remaining inductances of the filter. Since the same core material serves for both windings 7 as well as winding 11 and since. the arrange ment disclosed has little or no'external magnetic field it follows that the use of the de vice in electric wave filters and the like re: sults in an economy of both material and space. V

In case the windings 7 and 11 of Fig. 2 are em loyed in inde endent circuits such that di erent alternating currents would be flowing through the two windings, a small the mutual inductance examountof cross-talk between the two wind- I 31, 32 and 33 of the type the two windings of the unitary or fibre coremay be employed. Y Such'a corn J bination is shown in Fig. 3 in whicha' spool 24 of insulating material is'employed instead of magnetic material for separating and supporting the two windings.- Thesoleno dal winding 25 is wound on the spool in the usual manner after which the toroi lal winding 26 is uniforml inductance between the two windings since the planes of the turns are maintained mutually at right angles. In one particular combination coil constructed in accordance coeflicient coupling betweenfound to be, approximately. for all practical purposes Cross-talk between the two windings was very small and could be re:

with Fig. 3, the the winding was 97% which is negligible.

duced practically to zero by bringing one of the leads 27 of the solenoidal winding part of the way around the circumference of the. coil thereby counteracting the progression effect of the toroidal winding. Since the core;

in Fig. 3 is of air, no modulation, of course, occurs between the currents flowing in the. two windings. No appreciable effect in th constants of either winding due-to the presence'of the other windingwas noted. This. was in part due to the fact that a strandedconductor was used in'both windings, there.

by minimizing any current losses.

Fig. .5 shows how three combination coils of Fig. 3 may be arranged mutually at right angles so that there will be nomutual inductance eifects between the combination coils. The six windings of devices 31, 32 and 33 may therefore/be employed as the six inductances 12 to 17 of Fig-4gwithout danger of interferenee between the coils. A considerable turns of windto be employed in at .stanti'ally at right angles to woundaroundhe entireijfirst winding and being surface of the resulting toroid. Such a coinbination coil while having an external mag netic field will have substantially no mutual saving of space results from. the arrangement of the devices as in Fig. 5 since the devices may be mounted In close proximity to each other as long as they are kept at right angles to each other.

It is to be understood that various modifications of this invention may be made without departing in anywise from the spirit of this invention as defined in the appended claims. I

;What isclaimed is j y 1.. An. inductance device comprising a solenoidal winding, a form for supporting said winding and a second winding wound around .said form and said first winding,

said second winding having its turns subtheturns'of said substantially uniformly distributed over surface of said form and saidfirst winding.

2(An inductance device comprising a tonoidal core, a solenoidal'winding embedded in said core,.' and a second winding wound around said core, and having its turns at right angles to the turns of said first winding, the turns of said second winding being uniformly distributcd'over the surface of said core.

3. An inductance device comprising a toroidal-core of iron dust material, a solonoidal winding embedded in said core in a position arranged to give substantially no externalfield outside of said core for said winding,'- and .a toroidal winding wound around said core and havingv its turns at right,v angles to. the turns of said first winding, the turns of said second winding being around said form and said first winding, and having its turns substantially at right angles to theturn's of said first winding, and a conductor connected to said first winding and wound around said form and said first winding in a plane at right angles to the turns of said first winding. i

In witness whereof, I- hereunto subscribe my name this 25th day of June A. D., 1923.

FREDERICK J. GIVEN.

the entire external 

